Geographical variation in Plasmodium vivax relapse

Malaria Journal

Research

G Dennis Shanks¹  Thomas P Van Boeckel²  David L Smith³  Samir Bhatt⁴  Katherine E Battle⁴  Peter W Gething⁴  Rosalind E Howes⁴  Jane P Messina⁴  Nick Golding⁴  Markku S Karhunen⁴  Simon I Hay⁵  J Kevin Baird⁶ 

[1] Australian Army Malaria Institute, Enoggera, Queensland, Australia;Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA;Department of Epidemiology and Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA;Fogarty International Center, National Institutes of Health, Bethesda, MD, USA;Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK;Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK;Fogarty International Center, National Institutes of Health, Bethesda, MD, USA;Eijkman-Oxford Clinical Research Unit, Jalan Diponegoro No 69, Jakarta, Indonesia;Nuffield Department of Medicine, Centre for Tropical Medicine, University of Oxford, Oxford, UK;

关键词: Malaria;    Plasmodium vivax;    Map;    Relapse;    Periodicity;    Recurrence;    Recrudescence;    Strain;   

DOI  :  10.1186/1475-2875-13-144

 received in 2014-02-07, accepted in 2014-03-31,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundPlasmodium vivax has the widest geographic distribution of the human malaria parasites and nearly 2.5 billion people live at risk of infection. The control of P. vivax in individuals and populations is complicated by its ability to relapse weeks to months after initial infection. Strains of P. vivax from different geographical areas are thought to exhibit varied relapse timings. In tropical regions strains relapse quickly (three to six weeks), whereas those in temperate regions do so more slowly (six to twelve months), but no comprehensive assessment of evidence has been conducted. Here observed patterns of relapse periodicity are used to generate predictions of relapse incidence within geographic regions representative of varying parasite transmission.MethodsA global review of reports of P. vivax relapse in patients not treated with a radical cure was conducted. Records of time to first P. vivax relapse were positioned by geographic origin relative to expert opinion regions of relapse behaviour and epidemiological zones. Mixed-effects meta-analysis was conducted to determine which geographic classification best described the data, such that a description of the pattern of relapse periodicity within each region could be described. Model outputs of incidence and mean time to relapse were mapped to illustrate the global variation in relapse.ResultsDifferences in relapse periodicity were best described by a historical geographic classification system used to describe malaria transmission zones based on areas sharing zoological and ecological features. Maps of incidence and time to relapse showed high relapse frequency to be predominant in tropical regions and prolonged relapse in temperate areas.ConclusionsThe results indicate that relapse periodicity varies systematically by geographic region and are categorized by nine global regions characterized by similar malaria transmission dynamics. This indicates that relapse may be an adaptation evolved to exploit seasonal changes in vector survival and therefore optimize transmission. Geographic patterns in P. vivax relapse are important to clinicians treating individual infections, epidemiologists trying to infer P. vivax burden, and public health officials trying to control and eliminate the disease in human populations.

【 授权许可】

CC BY   
© Battle et al.; licensee BioMed Central Ltd. 2014